Regulator of combustion for thermic furnaces



P. FRION Jan. 24, 1939.

' REGULATOR OF COMBUS TION FOR THERMTC FURNACES Filed 001; 26, 1936Jnz/enfw" Patented Jan. 24, 1939 UNITED STATES REGULATOR OF COMBUSTIONFOR THERMIG FURNACES.

Paul Frion, Nanterre, France Application October 26, 1936,

In France November 1 Claim.

This invention relates to a regulator of combustion for thermicfurnaces.

Furnaces which are fed by means of pulverized or powdered coal are,generally speaking, provided with a burner having a constant crosssection to which said powdered coal and the air necessary for thecombustion of same are brought either jointly or separately under aconvenient pressure. Said devices, the construction and the arrangementof which are, as a. rule, unchangeable, are established once for all fordetermined conditions of operation and especially for a determinedcalorific production for securing the condition to take place in a pointstrictly located in front of the burner. The known devices of sucharrangement are in a position in some degree to regulate the combustionzone from the burner according to the needs, but they are not in aposition to reduce for a given combustible the distance existing betweensaid combustion zone and the burner. This results in an insufficientregulation which does not always allow the desirable conditions ofoperation to be obtained, more especially for what concerns theatmosphere of the furnace.

According to my invention, the mixture of powdered coal and of air issent into the chamher where the combustion has to take place along avein having a variable cross section, always similar in shape andprojected into the furnace with a variable speed thus allowing at anytime the keeping of the combustion zone at a determined point inside thefurnace.

In the accompanying drawing which shows by way of example aconstructional form of a device embodying the method according to myinvention:

Fig. l is a sectional I-! of Fig. 2,

Figs. 2 and 3 show in side View in two extreme different positions themechanism which controls the variation of cross section of the burner.

Figure 4 is a fragmental section illustrating a modified form of anigniting nozzle.

A frame I conveniently secured in the masonrywork of the entrance 2 ofthe furnace is provided with journals 3 in any convenient number (fourin the example shown in the drawing) receiving the ends of links 4 theother ends of which receive, through pivots 5, bars 6 each pivotallyconnected by its free end upon a journal 7 located on a common support 8having the shape of a crown, rotatably located in the annular frame I.

A controlling link 9 connected with one of journals 1 is articulated atthe end of a. screw view taken along the line which is lightedand SerialNo. 107,677

threaded rod 0 provided with hand-wheel H which allows the whole to varyits position for bringing the parts from the position of Fig. 2 to theposition of Fig. 3 which correspond to the minimum cross sectional areaand to the maximum cross sectional area of the orifice of the burner,respectively.

Each of the bars 6 is in the form of a shutter, the shutters beingconveniently located so as to cover one another in part, said coveringbeing 10 more or less important according to the position of said barsor shutters 5. somewhat in the manner of an iris diaphragm of aphotographic carnera, the Whole of bars 6 being shown in a purelydiagrammatical way at I2 in Fig. 1.

The furnace itself comprises any desired construction and the feeding ofpulverized coal of said furnace may offer any desired arrangement notshown in the drawing.

The operation is as follows: 20

For the starting of the furnace, the lighting of same is first effectedin the'usual manner by sending through nozzle l3 a combustible gasprojects a flame inside the furnace in which it causes the inflammationof 25 the pulverized coal which is sent at the same time into saidfurnace in the usual manner.

Once said pulverized coal is perfectly lighted, the feeding ofcombustible gas through nozzle l3 of said furnace being 30 of pulverizedcoal. point where the beginning of the combustion zone is to be placedinside the furnace, the hand-wheel I l is acted upon for causing by therotation of part 8 the displacement 35 of bars or shutters 6 which maybe brought into one of the extreme positions of Figs. 2 and 3, or anintermediate position thus determining the formation, between said barsor shutters, of a free orifice the cross section of which may have anarea varying from that shown in Fig. 2 to that shown in Fig. 3. It isthus possible to obtain a conveniently changeable area of the crosssection of the feeding burner of the furnace with a corresponding speedof the combustible mixture constituted with pulverized coal and air.

Due to the described arrangement, however, the shape of the crosssection of the jet of combustible mixture is constantly the same withthe cross section chosen at the time the device 50 is constructed. It isthus possible to obtain the desired variation of the conditions ofoperation of the furnace while however keeping in an absolute manner thecombustion zone in the axis of the burner, an essential condition for aconvenient operation of a furnace and more especially of a rotatingfurnace.

It is of course possible to vary the cross section area of the burner bymeans of any controlling device instead of being controlled through thehand-wheel H.

The number of parts such as bars or shutters 6 and links 4 may also varyaccording to circumstances and according to the shape which it isdesired to give to the orifice of said burner.

It is possible to locate in the vicinity of the burner, for instance inthe path of the mixture of pulverized coil and air, an additional burneror any other pre-heating device which permits the bringing of saidmixture to a high temperature favouring the inflammation of the same inthe furnace, thus also allowing the variation of position of theinflammation point of the combustible mixture, for varying the beginningof the combustion zone in said furnace.

In the constructional form of Fig. 1, a nozzle l3 located in the axis offrame i is provided with convenient perforations, and fed by a conduitI4 which brings to the orifice of said burner a combustible gas eitheralone or mixed with air, and the combustion of which inside the vein ofpulverized coal and air causes a convenient heating of said vein to takeplace.

Conduit [4 may be provided with convenient regulating and obturatingmembers such as vanes, valves or the like, located at any place andwhich may be controlled either by hand or automatically more especiallyfor lighting the furnace. In that latter case lighting gas or anothercombustible fluid is sent at the time of lighting of the furnace,through nozzle [3, and the combustion of said fluid at the entranceorifice of the burner heats the mixture of pulverized coal and of air,the feeding of combustible gas through nozzle [3 being cut ofi once theoperation of the furnace conveniently started. Such a cutting off may beobtained either by hand or automatically in any convenient manner.

It is also possible and more especially when no hot air is available forthe operation of the furnace, to maintain a feeding of lighting gas orof other combustible fluid through nozzle I3 during the normal operationof the furnace, in order to obtain a conveniently adjustable preheatingof the combustible mixture sent into the furnace.

Nozzle l3 may, of course, be located in any point of the burner andcould also offer the shape of a crown l5 as in Fig. 4, said crown beinglocated in any convenient place in front of the burner, the additionalburner constituted either by the central nozzle 13 or the annular nozzlel5, being fed by any convenient combustible either gaseous or liquid.

The several parts may be made of any convenient substance owing to thefact that combustion zone may always be kept sufficiently far from theparts of the burner for preventing said parts from being overheated.

My invention applies to any furnaces fed with pulverized coal or anyother combustible such as for instance lighting gas, high furnace gas,gazo gen gas or the like for any furnaces and more particularly forrotating furnaces.

What I claim is:

In a device for regulating the combustion of pulverized coal infurnaces, the combination with an annular support including a stationaryelement and a rotatable element through which pulverized coal and airare passed into the furnace, a plurality of bars constituting shutterseach having one end pivoted to the rotatable element of the support insuch manner as to form a substantially movable square defining the shapeof the opening, links pivoted to the outer ends of the bars and to thestationary element of the support, an operating member operably mountedon the stationary element of the support and operably connected to therotatable element of the support and to one of the bars, and a controlmember cooperating with the operating member for adjusting the latterand consequently the position of the bars to vary the size of theopening defined thereby without altering the shape thereof.

PAUL FRION.

